In this study, we propose to study Emergency Department patients under physiologic stress from severe pain, agitation, drug overdose, and excited delirium in order to compare markers of acidosis in patients at risk for unexplained-in-custody-death (UICD) in order to determine the relationship of these markers to what has been found in simulated law enforcement encounters. This information will help clarify the levels of stress associated with arrest and restraint conditions, allowing us to determine what aspects and levels of stress may be associated with the fatal mechanisms of UICD, and to identify markers that would inform death investigators of the mechanism of UICD. At the conclusion of this project, we will be able to report details explaining the relationship of the physiologic and metabolic effects of stress from restraint in excited delirium to other peri-arrest conditions and our previous work in simulated law enforcement encounters.